In adults with T2D, 4 weeks of daily kombucha consumption lowered fasting blood glucose more than a sensory-matched placebo drink, whereas in an 8-week trial in adults with non-alcoholic fatty liver disease, adding dairy kefir to a calorie-restricted diet did not significantly change fasting glucose, insulin, or HOMA-IR compared with diet alone, despite modest benefits on HDL-cholesterol and fat-free mass. The gene discussed is INS; the disease is metabolic dysfunction-associated steatotic liver disease.